SQL Server/T-SQL Tutorial/Aggregate Functions/Max
Содержание
- 1 Aggregate function, order by desc, group by
- 2 A summary query that works on non-numeric columns
- 3 Finding the Last Row in Employee Using MAX()
- 4 Finding the smallest and largest selling prices.
- 5 MAX returns the largest value in a column of all selected records by the query of any char, number, or datetime datatype.
- 6 The use of the aggregate function MAX in subquery
Aggregate function, order by desc, group by
<source lang="sql">
4> create table Billings ( 5> BankerID INTEGER, 6> BillingNumber INTEGER, 7> BillingDate datetime, 8> BillingTotal INTEGER, 9> TermsID INTEGER, 10> BillingDueDate datetime , 11> PaymentTotal INTEGER, 12> CreditTotal INTEGER 13> 14> ); 15> GO 1> 2> INSERT INTO Billings VALUES (1, 1, "2005-01-22", 165, 1,"2005-04-22",123,321); 3> GO (1 rows affected) 1> INSERT INTO Billings VALUES (2, 2, "2001-02-21", 165, 1,"2002-02-22",123,321); 2> GO (1 rows affected) 1> INSERT INTO Billings VALUES (3, 3, "2003-05-02", 165, 1,"2005-04-12",123,321); 2> GO (1 rows affected) 1> INSERT INTO Billings VALUES (4, 4, "1999-03-12", 165, 1,"2005-04-18",123,321); 2> GO (1 rows affected) 1> INSERT INTO Billings VALUES (5, 5, "2000-04-23", 165, 1,"2005-04-17",123,321); 2> GO (1 rows affected) 1> INSERT INTO Billings VALUES (6, 6, "2001-06-14", 165, 1,"2005-04-18",123,321); 2> GO (1 rows affected) 1> INSERT INTO Billings VALUES (7, 7, "2002-07-15", 165, 1,"2005-04-19",123,321); 2> GO (1 rows affected) 1> INSERT INTO Billings VALUES (8, 8, "2003-08-16", 165, 1,"2005-04-20",123,321); 2> GO (1 rows affected) 1> INSERT INTO Billings VALUES (9, 9, "2004-09-17", 165, 1,"2005-04-21",123,321); 2> GO (1 rows affected) 1> INSERT INTO Billings VALUES (0, 0, "2005-10-18", 165, 1,"2005-04-22",123,321); 2> GO (1 rows affected) 1> 2> 3> 4> create table Bankers( 5> BankerID Integer, 6> BankerName VARCHAR(20), 7> BankerContactLName VARCHAR(20), 8> BankerContactFName VARCHAR(20), 9> BankerCity VARCHAR(20), 10> BankerState VARCHAR(20), 11> BankerZipCode VARCHAR(20), 12> BankerPhone VARCHAR(20) 13> ) 14> GO 1> 2> insert into Bankers values (1, "ABC Inc.","Joe","Smith","Vancouver","BC","11111","111-111-1111"); 3> GO (1 rows affected) 1> insert into Bankers values (2, "DEF Inc.","Red","Rice", "New York", "DE","22222","222-222-2222"); 2> GO (1 rows affected) 1> insert into Bankers values (3, "HJI Inc.","Kit","Cat", "Paris", "CA","33333","333-333-3333"); 2> GO (1 rows affected) 1> insert into Bankers values (4, "QWE Inc.","Git","Black","Regina", "ER","44444","444-444-4444"); 2> GO (1 rows affected) 1> insert into Bankers values (5, "RTY Inc.","Wil","Lee", "Toronto", "YU","55555","555-555-5555"); 2> GO (1 rows affected) 1> insert into Bankers values (6, "YUI Inc.","Ted","Larry","Calgary", "TY","66666","666-666-6666"); 2> GO (1 rows affected) 1> insert into Bankers values (7, "OIP Inc.","Yam","Act", "San Franc","FG","77777","777-777-7777"); 2> GO (1 rows affected) 1> insert into Bankers values (8, "SAD Inc.","Hit","Eat", "Orland", "PO","88888","888-888-8888"); 2> GO (1 rows affected) 1> insert into Bankers values (9, "DFG Inc.","Sad","Lee", "Wisler", "PL","99999","999-999-9999"); 2> GO (1 rows affected) 1> insert into Bankers values (0, "GHJ Inc.","Bit","Lee", "Ticker", "MN","00000","000-000-0000"); 2> GO (1 rows affected) 1> 2> 3> SELECT BankerName, MAX(BillingDate) AS LatestInv 4> FROM Bankers JOIN Billings ON Bankers.BankerID = Billings.BankerID 5> GROUP BY BankerName 6> ORDER BY LatestInv DESC 7> 8> 9> drop table Billings; 10> drop table Bankers; 11> GO BankerName LatestInv
-----------------------
GHJ Inc. 2005-10-18 00:00:00.000 ABC Inc. 2005-01-22 00:00:00.000 DFG Inc. 2004-09-17 00:00:00.000 SAD Inc. 2003-08-16 00:00:00.000 HJI Inc. 2003-05-02 00:00:00.000 OIP Inc. 2002-07-15 00:00:00.000 YUI Inc. 2001-06-14 00:00:00.000 DEF Inc. 2001-02-21 00:00:00.000 RTY Inc. 2000-04-23 00:00:00.000 QWE Inc. 1999-03-12 00:00:00.000 (10 rows affected)</source>
A summary query that works on non-numeric columns
<source lang="sql">
5> 6> 7> create table Bankers( 8> BankerID Integer, 9> BankerName VARCHAR(20), 10> BankerContactLName VARCHAR(20), 11> BankerContactFName VARCHAR(20), 12> BankerCity VARCHAR(20), 13> BankerState VARCHAR(20), 14> BankerZipCode VARCHAR(20), 15> BankerPhone VARCHAR(20) 16> ) 17> GO 1> 2> insert into Bankers values (1, "ABC Inc.","Joe","Smith","Vancouver","BC","11111","111-111-1111"); 3> GO (1 rows affected) 1> insert into Bankers values (2, "DEF Inc.","Red","Rice", "New York", "DE","22222","222-222-2222"); 2> GO (1 rows affected) 1> insert into Bankers values (3, "HJI Inc.","Kit","Cat", "Paris", "CA","33333","333-333-3333"); 2> GO (1 rows affected) 1> insert into Bankers values (4, "QWE Inc.","Git","Black","Regina", "ER","44444","444-444-4444"); 2> GO (1 rows affected) 1> insert into Bankers values (5, "RTY Inc.","Wil","Lee", "Toronto", "YU","55555","555-555-5555"); 2> GO (1 rows affected) 1> insert into Bankers values (6, "YUI Inc.","Ted","Larry","Calgary", "TY","66666","666-666-6666"); 2> GO (1 rows affected) 1> insert into Bankers values (7, "OIP Inc.","Yam","Act", "San Franc","FG","77777","777-777-7777"); 2> GO (1 rows affected) 1> insert into Bankers values (8, "SAD Inc.","Hit","Eat", "Orland", "PO","88888","888-888-8888"); 2> GO (1 rows affected) 1> insert into Bankers values (9, "DFG Inc.","Sad","Lee", "Wisler", "PL","99999","999-999-9999"); 2> GO (1 rows affected) 1> insert into Bankers values (0, "GHJ Inc.","Bit","Lee", "Ticker", "MN","00000","000-000-0000"); 2> GO (1 rows affected) 1> 2> SELECT MIN(BankerName) AS FirstBanker, 3> MAX(BankerName) AS LastBanker, 4> COUNT(BankerName) AS NumberOfBankers 5> FROM Bankers 6> GO FirstBanker LastBanker NumberOfBankers
-------------------- ---------------
ABC Inc. YUI Inc. 10 (1 rows affected) 1> 2> 3> drop table Bankers; 4> GO 1></source>
Finding the Last Row in Employee Using MAX()
<source lang="sql">
9> 10> CREATE TABLE employee( 11> id INTEGER NOT NULL PRIMARY KEY, 12> first_name VARCHAR(10), 13> last_name VARCHAR(10), 14> salary DECIMAL(10,2), 15> start_Date DATETIME, 16> region VARCHAR(10), 17> city VARCHAR(20), 18> managerid INTEGER 19> ); 20> GO 1> INSERT INTO employee VALUES (1, "Jason" , "Martin", 5890,"2005-03-22","North","Vancouver",3); 2> GO (1 rows affected) 1> INSERT INTO employee VALUES (2, "Alison", "Mathews",4789,"2003-07-21","South","Utown",4); 2> GO (1 rows affected) 1> INSERT INTO employee VALUES (3, "James" , "Smith", 6678,"2001-12-01","North","Paris",5); 2> GO (1 rows affected) 1> INSERT INTO employee VALUES (4, "Celia" , "Rice", 5567,"2006-03-03","South","London",6); 2> GO (1 rows affected) 1> INSERT INTO employee VALUES (5, "Robert", "Black", 4467,"2004-07-02","East","Newton",7); 2> GO (1 rows affected) 1> INSERT INTO employee VALUES (6, "Linda" , "Green" , 6456,"2002-05-19","East","Calgary",8); 2> GO (1 rows affected) 1> INSERT INTO employee VALUES (7, "David" , "Larry", 5345,"2008-03-18","West","New York",9); 2> GO (1 rows affected) 1> INSERT INTO employee VALUES (8, "James" , "Cat", 4234,"2007-07-17","West","Regina",9); 2> GO (1 rows affected) 1> INSERT INTO employee VALUES (9, "Joan" , "Act", 6123,"2001-04-16","North","Toronto",10); 2> GO (1 rows affected) 1> 2> select * from employee; 3> GO id first_name last_name salary start_Date region city managerid
---------- ---------- ------------ ----------------------- ---------- -------------------- -----------
1 Jason Martin 5890.00 2005-03-22 00:00:00.000 North Vancouver 3
2 Alison Mathews 4789.00 2003-07-21 00:00:00.000 South Utown 4
3 James Smith 6678.00 2001-12-01 00:00:00.000 North Paris 5
4 Celia Rice 5567.00 2006-03-03 00:00:00.000 South London 6
5 Robert Black 4467.00 2004-07-02 00:00:00.000 East Newton 7
6 Linda Green 6456.00 2002-05-19 00:00:00.000 East Calgary 8
7 David Larry 5345.00 2008-03-18 00:00:00.000 West New York 9
8 James Cat 4234.00 2007-07-17 00:00:00.000 West Regina 9
9 Joan Act 6123.00 2001-04-16 00:00:00.000 North Toronto 10
(9 rows affected) 1> 2> 3> 4> SELECT 5> * 6> FROM 7> Employee 8> WHERE 9> ID = 10> ( 11> SELECT 12> MAX (ID) 13> FROM 14> Employee 15> ) 16> 17> 18> 19> drop table employee; 20> GO id first_name last_name salary start_Date region city managerid
---------- ---------- ------------ ----------------------- ---------- -------------------- -----------
9 Joan Act 6123.00 2001-04-16 00:00:00.000 North Toronto 10
(1 rows affected)</source>
Finding the smallest and largest selling prices.
<source lang="sql">
3> CREATE TABLE CD ( 4> CD_ID integer NOT NULL PRIMARY KEY, 5> CD_Title varchar(40), 6> Composer_ID integer NOT NULL, 7> Classif_ID integer NOT NULL, 8> SalesPrice money, 9> AverageCost money) 10> GO 1> INSERT into CD VALUES(2000,"John",100,1,16.99,6.99) 2> INSERT into CD VALUES(2001,"Chicago 16",107,1,14.99,5.99) 3> INSERT into CD VALUES(2002,"Chicago 17",107,1,14.99,5.99) 4> INSERT into CD VALUES(2003,"Chicago 18",107,1,14.99,5.99) 5> INSERT into CD VALUES(2004,"Greatest Hits",107,1,16.99,7.99) 6> INSERT into CD VALUES(2005,"Midnight",101,3,14.99,5.99) 7> INSERT into CD VALUES(2006,"Mode",115,3,14.99,5.99) 8> INSERT into CD VALUES(2007,"Ultra",115,3,15.99,5.99) 9> INSERT into CD VALUES(2008,"Mindcrime",102,4,14.99,5.99) 10> INSERT into CD VALUES(2009,"Empire",102,4,14.99,5.99) 11> INSERT into CD VALUES(2010,"Land",102,4,12.99,4.99) 12> INSERT into CD VALUES(2011,"Night",103,4,11.99,3.99) 13> INSERT into CD VALUES(2012,"Pyromania",103,4,14.99,5.99) 14> INSERT into CD VALUES(2013,"Hysteria",103,4,14.99,5.99) 15> INSERT into CD VALUES(2014,"Hits",103,4,13.99,4.99) 16> INSERT into CD VALUES(2015,"Hits 2",104,2,15.99,6.99) 17> INSERT into CD VALUES(2016,"Greatest",105,2,14.99,5.99) 18> INSERT into CD VALUES(2017,"Hits 3",106,1,13.99,5.99) 19> INSERT into CD VALUES(2018,"Deep",108,1,12.99,2.99) 20> INSERT into CD VALUES(2019,"Turning",109,1,14.99,5.99) 21> INSERT into CD VALUES(2020,"TheHits",109,1,16.99,7.99) 22> INSERT into CD VALUES(2021,"Cars",110,1,9.99,3.99) 23> INSERT into CD VALUES(2022,"Anthology",110,1,25.99,11.99) 24> INSERT into CD VALUES(2023,"City",110,1,14.99,5.99) 25> INSERT into CD VALUES(2024,"Rick",111,1,11.99,2.99) 26> INSERT into CD VALUES(2025,"Live",112,1,19.99,8.99) 27> INSERT into CD VALUES(2026,"Pat",113,1,16.99,6.99) 28> INSERT into CD VALUES(2027,"Big",114,1,14.99,5.99) 29> INSERT into CD VALUES(2028,"Hurting",114,1,11.99,3.99) 30> INSERT into CD VALUES(2029,"Vol 1",116,1,9.99,2.99) 31> INSERT into CD VALUES(2030,"Vol 2",116,1,9.99,2.99) 32> GO (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) 1> 2> 3> SELECT MAX(SalesPrice),MIN(SalesPrice) from CD 4> GO
---------------------
25.9900 9.9900
(1 rows affected) 1> 2> drop table CD; 3> GO</source>
MAX returns the largest value in a column of all selected records by the query of any char, number, or datetime datatype.
<source lang="sql">
4> 5> CREATE TABLE sales( 6> stor_id char(4) NOT NULL, 7> ord_num varchar(20) NOT NULL, 8> ord_date datetime NOT NULL, 9> qty smallint NOT NULL, 10> payterms varchar(12) NOT NULL, 11> title_id varchar(80) 12> ) 13> GO 1> insert sales values("1", "QA7442.3", "09/13/94", 75, "ON Billing","1") 2> insert sales values("2", "D4482", "09/14/94", 10, "Net 60", "1") 3> insert sales values("3", "N914008", "09/14/94", 20, "Net 30", "2") 4> insert sales values("4", "N914014", "09/14/94", 25, "Net 30", "3") 5> insert sales values("5", "423LL922", "09/14/94", 15, "ON Billing","3") 6> insert sales values("6", "423LL930", "09/14/94", 10, "ON Billing","2") 7> GO (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) (1 rows affected) 1> 2> 3> select MAX(ord_date) from sales; 4> GO
1994-09-14 00:00:00.000 (1 rows affected) 1> 2> drop table sales; 3> 4> GO</source>
The use of the aggregate function MAX in subquery
<source lang="sql">
8> 9> 10> CREATE TABLE employee( 11> id INTEGER NOT NULL PRIMARY KEY, 12> first_name VARCHAR(10), 13> last_name VARCHAR(10), 14> salary DECIMAL(10,2), 15> start_Date DATETIME, 16> region VARCHAR(10), 17> city VARCHAR(20), 18> managerid INTEGER 19> ); 20> GO 1> INSERT INTO employee VALUES (1, "Jason" , "Martin", 5890,"2005-03-22","North","Vancouver",3); 2> GO (1 rows affected) 1> INSERT INTO employee VALUES (2, "Alison", "Mathews",4789,"2003-07-21","South","Utown",4); 2> GO (1 rows affected) 1> INSERT INTO employee VALUES (3, "James" , "Smith", 6678,"2001-12-01","North","Paris",5); 2> GO (1 rows affected) 1> INSERT INTO employee VALUES (4, "Celia" , "Rice", 5567,"2006-03-03","South","London",6); 2> GO (1 rows affected) 1> INSERT INTO employee VALUES (5, "Robert", "Black", 4467,"2004-07-02","East","Newton",7); 2> GO (1 rows affected) 1> INSERT INTO employee VALUES (6, "Linda" , "Green" , 6456,"2002-05-19","East","Calgary",8); 2> GO (1 rows affected) 1> INSERT INTO employee VALUES (7, "David" , "Larry", 5345,"2008-03-18","West","New York",9); 2> GO (1 rows affected) 1> INSERT INTO employee VALUES (8, "James" , "Cat", 4234,"2007-07-17","West","Regina",9); 2> GO (1 rows affected) 1> INSERT INTO employee VALUES (9, "Joan" , "Act", 6123,"2001-04-16","North","Toronto",10); 2> GO (1 rows affected) 1> 2> select * from employee; 3> GO id first_name last_name salary start_Date region city managerid
---------- ---------- ------------ ----------------------- ---------- -------------------- -----------
1 Jason Martin 5890.00 2005-03-22 00:00:00.000 North Vancouver 3
2 Alison Mathews 4789.00 2003-07-21 00:00:00.000 South Utown 4
3 James Smith 6678.00 2001-12-01 00:00:00.000 North Paris 5
4 Celia Rice 5567.00 2006-03-03 00:00:00.000 South London 6
5 Robert Black 4467.00 2004-07-02 00:00:00.000 East Newton 7
6 Linda Green 6456.00 2002-05-19 00:00:00.000 East Calgary 8
7 David Larry 5345.00 2008-03-18 00:00:00.000 West New York 9
8 James Cat 4234.00 2007-07-17 00:00:00.000 West Regina 9
9 Joan Act 6123.00 2001-04-16 00:00:00.000 North Toronto 10
(9 rows affected) 1> 2> 3> SELECT * FROM employee 4> WHERE start_date = (SELECT MAX(start_date) FROM employee WHERE id > 3) 5> GO id first_name last_name salary start_Date region city managerid
---------- ---------- ------------ ----------------------- ---------- -------------------- -----------
7 David Larry 5345.00 2008-03-18 00:00:00.000 West New York 9
(1 rows affected) 1> 2> drop table employee; 3> GO</source>
